Burglar-alarm.



.l. L. McMAHON.

BURGLAR ALARM.

APPLICATION FILED JUNE :7. 1915.

1 ,1 84,5 50. Patented May 23, 1916.

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JOHN LUKE MoMLAI-ION, OF NEW YORK, N. Y.

BURGLAR-ALARM.

Specification of Letters Patent.

Patented May 23, 1916.

Application filed June 17, 1915. Serial No. 34,623.

To all whom it may concern:

Be it known that I, JOHN LUKE MGMA- HON, a citizen of the United States,and a resident of the city of New York, borough. of Manhattan, in thecounty and State of New York, have invented a new and ImprovedBurglar-Alarm, of which the following is a full, clear, and exactdescription.

The object of the invention is to provide a new and improved burglaralarm more especially designedfor sounding a whistle on the opening of adoor, window or like device by a burglar or other unauthorized person,and arranged to enable the occupant of the room to render the burglaralarm inactive on the owner entering the room.

In order to accomplish the desired result, use is made of a whistle, avalve fixed adjacent a door, window or similar movable part andconnected with the mouth of the said whistle, the valve being providedat its valve stem with a cam and the said valve being connected with asource of fluid pressure, and an operating member attached to themovable part and engaging the said cam at the time the door and thevalve are in closed positions, the said operating member imparting aswinging motion to the said cam to open the valve at the time the dooris opened to allow the fluid pressure to pass from the said source offluid pressure into the whistle and to sound the same.

A practical embodiment of the invention is represented in theaccompanying drawings forming a part of this speclficatlon, rnl whichsimilar characters of reference indi-f cate corresponding parts in allthe views.

Figure 1 is a perspective view of the burglar alarm as applied to adoor; Flg. 2 is a face view of the key-controlled bolt forthe valve;Fig. 3 is a cross section of the same as ap lied; and Fig. 4 is aperspective view of the olt carrying the operating member for the valve.v

As shown in Figs. 1 and 3, a bracket A is attached to the inner face ofthe top of a door casing B adjacent a door G. On the bracket A issecured an elbow D connected at one end by a nipple E with the mouth orentrance end of a whistle F, preferably one. of the policeman type. Theother end of the elbow D is connected with a Valve G connected by a pipeH with a tank or reservoir I containing compressed air or other suitablefluid under pressure, the outflow of the fluid pressure from thereservoir I to the pipe H being controlled by a valve J. The valve J isnormally open and the valve G 1s normally closed.

The bottom of the valve stem G of the valve G is provided with ahorizontally disposed cam K engaged by a pin L extending upwardly on thefree end of an arm N disposed horizontally and attached to the upper endof a bolt 0 mounted to slide vertically in a bracket P attached to thedoor C. The bolt 0 is normally in uppermost posltion so that the pin Lengages the cam K and when the door C is opened by a traveler or otherunauthorized person then the pin L imparts a swinging motion to the camK whereby the valve G is opened and the fluid pressure from thereservoir I passes by way of the pipe H, valve G, elbow D and nipple Einto the whistle F to sound the same, thus giving an alarm.

The bolt 0 is key-controlled on the outside of the door to permit theowner or user of the room to retract the bolt 0 prior to openingthe'door so that the pin L is moved out 'of engagement with the cam Kand hence the valve G is not opened and the whistle F is not sounded.After the owner has entered the room he can move the bolt 0 upward toreengage the pin L with the cam K. In order to control the bolt 0 use ismade of a key-controlled roll-back Q, having a hub Q, j ournaled in thecasing P and adapted to be engaged by a key inserted through a keyhole Cformed in the door C. The roll-back Q controls a tumbler. R pivoted atIt on the casing P and pressed on by a spring R to normally engage thetumbler R with a lug 0 formed on the bolt 0 to hold the latter normallyin shot-out position. The bolt 0 is provided with a lug 0 adapted to beengaged in one direction by the rol1-back Q and adapted to be en gagedin an opposite direction by an arm Q formed on the roll-back Q. When thekey is inserted in the roll-back Q and turned a swinging motion is givento the roll-back to cause the latter to swing the tumbler R out ofengagement with the lug O and then the roll-back engages the lug O toretract the bolt 0 for the purpose previously mentioned. When the key isturned in the opposite direction or an upward pressure is exerted on thearm N then the bolt 0 is shot out to normal position and locked in placeby the tumbler R engaging the lug O.

The burglar alarm shown and described is very simple in construction andcan be readily attached to a door, window or other movable part, so thatwhen the latter is opened the valve G is opened to allow fluid pressureto pass into the whistle F to sound the same.

Having thus described my invention, I claim as new and desire to secureby Letters Patent:

1. A burglar alarm, comprising a whistle, a valve fixed adjacent thedoor, and connected with the mouth of the said whistle, the valve beingprovided at its valve stem with a cam, a source of fluid pressureconnected with the said valve, and an operating member attached to thedoor and movable into and out of engagement with the said valve stemcam, the said operating member engaging the cam when the door is closedand imparting a swinging motion to the said cam to open the valve whenthe door is opened to allow fluid pressure to pass from the said sourceof fluid pressure into the whistle and sound the same.

2. A burglar alarm, comprising a whistle, a valve fixed adjacent thedoor, and connected with the mouth of the said whistle, the valve beingprovided at its valve stem with a cam, a source of fluid pressureconnected with the said valve, and a lock on the movable part' having akey-controlled 8. A burglar'alarm, comprising a whistle,

a valve connected with the whistle, the valve and whistle being securedto a door frame, a source of fluid pressure connected with the valve, asliding member secured to the door a cam and lug engaging means betweenthe sliding'member and the valve stem, the said cam and lug being inengagement with each other when the door is closed, whereby when thedoorisopened the valve will be opened and the whistle sounded, and means foroperating the sliding member. V

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

Witnesses:

THEO. G. HosTER, PHILIP D. RoLLHAUs.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. 0.?

JOHN LUKE MQMAHON.

